| 摘要 |
PURPOSE:To produce a highly abrasion resistant bent pipe at a low cost by subjecting a straight pipe made of Cr-Mo low alloy steel of high carbon type produced by a centrifugal casting method or the like to bending under specific conditions with high frequency heating. CONSTITUTION:A straight pipe is produced of a high carbon Cr-Mo type low alloy steel contg. 0.25-0.75% C, <2.00% Si, <2.00% Mn, <2.00% Cr, and <1.00% Mo by a centrifugal casting method or the like. This as a blank pipe is heated to a 700-1,100 deg.C temp. range by a high frequency induction heating device; thence it is subjected to bending at a radius of bending less than 5 times the diameter of the straight pipe under working conditions of <=1.0mm./sec feed speeds and <=5 deg.C/ min rates of cooling from working temp. down to 400 deg.C, whereby the bent pipe of high hardness and superior abrasion resistance is produed easily at a low cost. |
